The ability to effectively remove emboli and/or contrast agents during medical procedures in the circulatory system would have broad implications on how vascular disease and conditions are treated and complications are managed.
The use of procedures such as balloon angioplasty, laser angioplasty, chemical and mechanical methods of altering vessel walls, etc. pose a great risk to the patient as emboli may be released during such procedures. Once released, these emboli have a high likelihood of getting lodged into the vessels at a point of constriction downstream of their release point, causing the vessel to become occluded. Organs and tissues dependent on the occluded circulatory branch will have a depleted level of circulation and therefore suffer an increased likelihood of damage, including the possibility of organ failure and/or stroke.
Evidence exists that suggests that embolization is a serious complication. It can occur without a clinical triggering event, as in the case of a gradual increase in blood pressure, as well as during interventional procedures within the vasculature. Men in their sixth and seventh decades of life are most prone to cholesterol embolization, while the kidneys, spleen, pancreas, gastrointestinal tract, adrenals, liver, brain and testes are the organs most frequently reported as those affected. (Vidt D. G., Cholesterol emboli: a common cause of renal failure. Annu Rev Med 1997; 48:375-85.)
Common clinical procedures that might trigger an embolization event include stenting, fluoroscopy, angioplasty, and other operative as well as diagnostic procedures that occur in sites that communicate fluid within the vasculature. Furthermore, it is difficult to identify embolization as the source of any symptoms that are presented, because these symptoms can be similarly presented by several mechanisms other than embolization.
Other related problems may require the extraction of materials or fluids from the body to prevent embolization. For example, in the event of a patient being placed on a heart lung machine, the aorta will need to be clamped. Upon release of the clamp or equivalent, debris and/or emboli produced or accumulated as a result of the clamping may be in danger of proceeding throughout the body, including the cerebral vasculature. The current invention would be useful in removing these materials or fluids at or around the time at which the circulation in this region is restored to normal.
Yet another problem that often occurs during diagnostic and interventional procedures involves the introduction of potentially harmful fluids, such as radiopaque dyes used during fluoroscopy. Three common issues that may render a fluid harmful to the patient include high doses of the agent, immunological responses (i.e. allergic reactions) to the fluid (Back M. R., Angiography with carbon dioxide (CO2) Surg Clin North Am 1998 August; 78(4):575-91) or heightened sensitivity of the patient to the fluid, as in the case of azotemic diabetics (Manske, C. L., Contrast Nephropathy in Azotemic Diabetic Patients Undergoing Coronary Angiography, The American Journal of Medicine, 1990 November, 89:615-620.) These may lead to organ failure or other complications. Renal failure due to the administration of contrast agent has been reported to be the third most common cause of in-hospital renal failure, surpassed only by hypotension and surgery. (Katzberg, R. W., Urography into the 21st Century: New Contrast Media, Renal Handling, Imaging Characteristics, and Nephrotoxicity. Radiology, 1997 August, 204(2):297-309.)